A high vacuum container includes an outer container body and an inner container body. When the outer container body is sleeved onto outside of the inner container body to form the high vacuum container, the position accuracy of the inner container inside the outer container body should be high to ensure the concentricity of the outer container body and the inner container body.
FIG. 1 is an assembling schematic diagram showing a conventional high vacuum container consisted of the inner container body and the outer container body. As shown in FIG. 1, an eight-point positioning method is used to position the inner container body 2′ inside the outer container body 1′ of the conventional high vacuum container, including the following steps:
(1) fixing the outer container body 1′ with several openings H′ defined onto the wall thereof and placing rails R inside the outer container body 1′;
(2) pushing a rail tooling 3′ against left side end cover 21′ and a movable tooling 4′ against right side end cover 22′ of the inner container body 2′ respectively, and then moving the inner container body 2′ by the rail tooling 3′ along the rails R laid on the bottom wall of the outer container body 1′ and the movable tooling 4′ hanged up along the direction A in FIG. 1, so as to the inner container body 2 is sleeved into the outer container body 1′,
(3) after placing the inner container body 2′ into the accommodating space of the outer container body 1′ by the rail tooling 3′ and the movable tooling 4′, then adjusting the relative position of the inner container body 2′ to the outer container body 1′ by adjusting the position of the rail tooling 3′ against the left side end cover 21′, thereby achieving the centralized positioning,
(4) fixing the relative position of the inner container body 2′ to the outer container body 1′ by eight supporting assemblies 5′ of the high vacuum container as shown in FIG. 2).
FIG. 2 is a sectional diagram showing the inner container body 2′ and the outer container body 1′ of the high vacuum container after assembling in FIG. 1. Only four supporting assemblies are shown in FIG. 2. The eight supporting assemblies 5′ of the high vacuum container are divided into two groups along the axis thereof, and four supporting assemblies 5′ in each group are arranged around the circumference of the inner and outer container bodies. Each supporting assembly 5′ includes a base plate 51′, an upper fixing pipe 52′, a heat insulating pipe 53′ and a cover plate 54′, and the supporting assemblies in the group at the rear portion of the high vacuum container further includes a lower fixing pipe 55′.
As shown in FIG. 1, before step (2), the base plate 51′ is welded onto the front portion of the inner container body 2′. But, for the supporting assemblies 5 at the rear portion of the high vacuum container, the base plates 51′ with the lower fixing pipes 55′ welded thereonto are welded onto the rear portion of the inner container body 2′. After the inner container body 2′ is transported to a predetermined place, the positions of the base plates 51′ is corresponding to those of the openings H′ of the outer container body 1′. Then, a heat insulating pipe 53′ with a predetermined length is inserted through each opening H′ of the outer container body 1′ to abut against the base plate 51′, and for the group of supporting assemblies 5′ at the rear portion of the high vacuum container, the heat insulating pipes 53′ are inserted into the lower fixing pipes 55′. Then, the upper axing pipes 52′ welded with cover plate 54′ is inserted through the openings H, and the cover plate 54′ covers the outer surface of the outer container body 1′, and the heat insulating pipe 53′ is inserted in the upper fixing pipe 52′. Thereby, the assembling and positioning process of the high vacuum container is finished.
The heat insulating pipes 53′ are arranged along the radial direction of the inner container body and the outer container body, and the length of the heat insulating pipe 53′ is predetermined from the theoretical calculation. For example, the length is half of the difference between the diameter of the outer container body and the diameter of the inner container body. In practical application, the eight-point positioning method has drawbacks as follows: because of the length of the heat insulating pipe being deduced from theoretical calculation, during the assembling process, the concentricity of the inner container body and the outer container body cannot be adjusted due to operation and manufacture errors, and the concentricity can not meet the requirement of tolerance in the scope of ≦±5 mm.